USDA zones 7a, 7b, 8a in Delaware
USDA plant hardiness zones 7a, 7b, 8a cover 10 locations across Delaware (average annual extreme minimum 0 to 15 °F): Bethel, DE, Dewey Beach, DE, Hockessin, DE, Lewes, DE, Millsboro, DE, Millville, DE, and 4 more. Average last spring frost across this state ranges March 29 (Dewey Beach) to April 7 (Wilmington), and growing seasons run 209–231 days (Hockessin to Lewes) — even within one state, because hardiness sets winter survival, not planting dates. Here all 3 of its hardiness zones share this page rather than sit on 3 thin ones. The table below gives every Delaware location's own frost dates; the printable planting calendar uses Millsboro, this state's median-season location.
- USDA zones
- 7a, 7b, 8a0 to 15 °F
- Last frost range
- Mar 29–Apr 7avg, 32°F
- First frost range
- Nov 2–Nov 14avg, 32°F
- Growing season range
- 209–231days
Locations in this group
Every location below keeps its own USDA zone, weather station, and frost dates — they are listed together here, not averaged. Find your town for its own numbers, or use the ZIP planner on the home page for an instant personalized answer.
| Location | Zone | Also covers | Nearest station | Last frost | First frost | Season (days) |
|---|---|---|---|---|---|---|
| Bethel | 7b | — | Salisbury 2n | Apr 2 | Nov 10 | 222 |
| Dewey Beach | 8a | — | Lewes | Mar 29 | Nov 14 | 231 |
| Hockessin | 7a | Chadds Ford, Chester Heights, Toughkenamon, Kennett Square, Dilworthtown, Cheyney University | Wilmington Porter Rsch | Apr 7 | Nov 4 | 209 |
| Lewes | 7b | — | Lewes | Mar 29 | Nov 14 | 231 |
| Millsboro * | 7b | Georgetown, Lincoln, Laurel, Long Neck, Millville, Milton, +4 more | Georgetown Sussex Co Ap | Apr 4 | Nov 6 | 217 |
| Millville | 8a | Bethany Beach | Georgetown Sussex Co Ap | Apr 4 | Nov 6 | 217 |
| Selbyville | 7b | Berlin, Bishopville | Ocean City Muni Ap | Apr 7 | Nov 2 | 209 |
| Smyrna | 7b | Cheswold, Frederica, Sudlersville, Slaughter Beach, Greensboro, Townsend, +15 more | Dover | Apr 4 | Nov 4 | 214 |
| Wilmington | 7b | Carneys Point, Greenville, Chester Heights, Claymont, Edgemoor, Village Green-Green Ridge, +5 more | Wilmington Porter Rsch | Apr 7 | Nov 4 | 209 |
| Woodside | 7a | — | Dover | Apr 4 | Nov 4 | 214 |
* Millsboro is this group's median-season location — the calendar below is computed from its data.
Data: NOAA NCEI U.S. Climate Normals 1991–2020 (public domain) and USDA Plant Hardiness Zone Map 2023. Planting windows synthesized from U.S. Cooperative Extension guides.
Planting calendar (Millsboro, representative)
Computed from Millsboro's average frost dates — the median-season location in this Delawarezones 7a, 7b, 8a group. hatched = start seeds indoors, solid green = plant out, teal = a fall sowing, and the terracotta dot marks the estimated first harvest. Ranges are extension-guide planning guidance, not guarantees — your own location's dates may run a week or two earlier or later (see the table above).
- Start indoors
- Plant out
- Fall sowing
- First harvest
| Crop | Frost tolerance | Start indoors | Plant out | First harvest | Fall planting | Season fit |
|---|---|---|---|---|---|---|
| Tomato | Tender | Feb 7 – Feb 21 | Apr 11 – Apr 18 | Jun 10 – Jun 30 | — | matures comfortably |
| Pepper | Very tender | Jan 24 – Feb 7 | Apr 18 – Apr 25 | Jun 17 – Jul 17 | — | matures comfortably |
| Cucumber | Tender | Mar 7 – Mar 14 | Apr 11 – Apr 18 | May 31 – Jun 20 | — | matures comfortably |
| Summer squash / zucchini | Tender | — | Apr 11 – Apr 18 | May 26 – Jun 10 | — | matures comfortably |
| Bush bean | Tender | — | Apr 11 – Apr 18 | May 31 – Jun 10 | Sep 7 – Sep 17 | matures comfortably |
| Sweet corn | Tender | — | Apr 4 – Apr 18 | Jun 3 – Jul 3 | — | matures comfortably |
| Basil | Very tender | Feb 21 – Mar 7 | Apr 11 – Apr 18 | May 11 – May 26 | — | matures comfortably |
| Lettuce | Half-hardy | Feb 21 – Mar 7 | Mar 7 – Mar 21 | Apr 21 – May 6 | Aug 24 – Sep 8 | matures comfortably |
| Pea | Hardy | — | Feb 21 – Mar 7 | Apr 17 – May 2 | Aug 14 – Aug 29 | matures comfortably |
| Spinach | Hardy | — | Feb 21 – Mar 7 | Apr 2 – Apr 12 | Sep 3 – Sep 13 | matures comfortably |
| Carrot | Half-hardy | — | Mar 14 – Mar 21 | May 13 – Jun 2 | Aug 4 – Aug 24 | matures comfortably |
| Broccoli | Half-hardy | Feb 7 – Feb 21 | Mar 7 – Mar 21 | May 1 – May 21 | Aug 9 – Aug 29 | matures comfortably |
Which crops fit this growing season
Using Millsboro's own 217-day growing season (32°F, NOAA 1991–2020 median) against each crop's real days-to-maturity range: 12 of 12 crops mature here with comfortable margin. A different location in the table above with a longer or shorter season will get a different mix — the ZIP planner on the home page gives your own.
Frost & freeze dates (Millsboro)
From NOAA's 1991–2020 Climate Normals at station USW00013764. The median (p50) is the average date; the 90%-safe column is the date the freeze has passed in about 9 years out of 10 — the conservative date to plant after or harvest before.
| Threshold | Last spring — avg | Last spring — 90%-safe | First fall — avg | First fall — 90%-safe | Season (days) |
|---|---|---|---|---|---|
| 36°F | Apr 16 | May 2 | Oct 27 | Nov 8 | 191 |
| 32°F (freeze) | Apr 4 | Apr 16 | Nov 6 | Nov 22 | 217 |
| 28°F | Mar 23 | Apr 5 | Nov 19 | Dec 6 | 244 |
| 24°F | Mar 10 | Mar 25 | Dec 4 | Dec 27 | 271 |
Growing degree days
Growing degree days (GDD) accumulate warmth above a base temperature over the year — a better predictor of crop development than the calendar alone. This group's median GDD (base 50°F) across all 10 locations is 4,171; Millsboro's own reading is shown below.
| Model | °F·days | Used for |
|---|---|---|
| Base 50°F (warm-season) | 4,225 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 6,911 | cool-season crops (brassicas, greens) |
Hardiness zones 7a, 7b, 8a in Delaware
Delaware's 3 hardiness zones (7a, 7b, 8a) — an average annual extreme minimum winter temperature range of 0 to 15 °F on the USDA's 2023 map — share this page Delaware is small enough that every one of its hardiness zones (7a, 7b, 8a) is combined onto this one page rather than split thin across several. Each location's own zone is in the table above. Hardiness sets winter survival, not planting dates; the frost calendar uses Millsboro, this page's representative location.
See all USDA hardiness zones across the site, or browse all Delaware locations.
Frequently asked questions
- What USDA hardiness zones does Delaware have?
- Delaware spans zones 7a, 7b, 8a — an average annual extreme minimum winter temperature range of 0 to 15 °F on the USDA's 2023 map — across 10 locations, each listed with its own zone in the table above. The zone does not set planting dates; see the frost calendar for that.
- Where in Delaware is the growing season longest?
- Lewes runs the longest season on this page at about 231 days; Hockessin is shortest at about 209 days — hardiness zone is not what separates them, but they sit at different weather stations, so their frost calendars differ.
- When should I plant tomatoes in Delaware?
- Using Millsboro's frost dates (this page's median-season location): start seeds indoors about Feb 7 – Feb 21, then transplant outside about Apr 11 – Apr 18. Your own location in the table above may differ by a week or two — use the ZIP planner on the home page for your exact station's dates.
- Does every location in Delaware have the same frost dates?
- No — they do not all share a weather station, so frost dates vary by a week or more across the 10 locations listed (see the table above for each location's own dates).
Sources & method
Frost, freeze, growing-season, and growing-degree-day figures are NOAA NCEI U.S. Climate Normals 1991–2020, one reading per location's own nearest station (see the table above). The hardiness zone is the USDA Plant Hardiness Zone Map 2023, matched to each location's ZIP. Planting windows are computed by counting from the average last and first frost using per-crop offsets synthesized from U.S. Cooperative Extension guides — the full method and citations are on the methodology page.